MSP430FR2476: EusciB I2C gets stuck in EUSCI_B_I2C_masterSendSingleByte function

#include "driverlib.h"
#include <stdio.h>
#include <string.h>

/* Global Defines */
#define CS_MCLK_DESIRED_FREQUENCY_IN_KHZ   16000  /**<  Target frequency for MCLK in kHz */
#define CS_MCLK_FLLREF_RATIO               488    /**<  MCLK/FLLRef Ratio */

int main(void)
{
    volatile uint32_t i;
    uint8_t transmitData;
    WDT_A_hold(WDT_A_BASE);

    GPIO_setAsInputPinWithPullUpResistor(GPIO_PORT_P3, GPIO_PIN2 | GPIO_PIN6);
    GPIO_setAsPeripheralModuleFunctionInputPin(
        GPIO_PORT_P3,
        GPIO_PIN2 + GPIO_PIN6,
        GPIO_PRIMARY_MODULE_FUNCTION
    );

    /*
     * Disable the GPIO power-on default high-impedance mode to activate
     * previously configured port settings
     */
    PMM_unlockLPM5();

    //Initialize transmit data packet
    transmitData = 0x01;

    //Initialize Master
    EUSCI_B_I2C_initMasterParam param = {0};
    param.selectClockSource = EUSCI_B_I2C_CLOCKSOURCE_SMCLK;
    param.i2cClk = CS_getSMCLK();
    param.dataRate = EUSCI_B_I2C_SET_DATA_RATE_400KBPS;
    param.byteCounterThreshold = 1;
    param.autoSTOPGeneration = EUSCI_B_I2C_NO_AUTO_STOP;
    EUSCI_B_I2C_initMaster(EUSCI_B1_BASE, &param);
    //Specify slave address
    EUSCI_B_I2C_setSlaveAddress(EUSCI_B1_BASE,
        0x48
        );

    //Set in transmit mode
    EUSCI_B_I2C_setMode(EUSCI_B1_BASE,
        EUSCI_B_I2C_TRANSMIT_MODE
        );

    //Enable I2C Module to start operations
    EUSCI_B_I2C_enable(EUSCI_B1_BASE);


    while(1)
    {
        EUSCI_B_I2C_masterSendSingleByte(EUSCI_B1_BASE,
            0xAA         //Send MSB of the address first
            );

        for(i=100000; i>0; i--);
    }
}

 would normally expect to see on the logic analyser a sequence of transmission attempts to address 0x48, all ending with a NAK since the peripheral is not connected. 
What I get is a single transmission as in the screen capture below

and then the SCL line stays low. 
By debugging the code, I found out that the program gets stuck in the eusci_b_i2c.c file, at line 192 at the following instruction of function EUSCI_B_I2C_masterSendSingleByte()

    //Poll for transmit interrupt flag.
    while (!(HWREG16(baseAddress + OFS_UCBxIFG) & UCTXIFG)) ;